JP2002004418A - Construction method and structure for self-base- isolation of rc type structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method and a structure for self-base- isolation whereby the natural frequency of an RC type structure can be made longer without use of a base isolator and an earthquake control device. SOLUTION: An unbounded prestressing steel member 3 is passed through a precast concrete beam 2 along the longitudinal direction of the beam, with each end of the steel member 3 anchored to a precast concrete column 1 to permit uplift of a column-and-beam connecting interface due to the elastic elongation and deformation of the steel member 3 under a horizontal force produced by an earthquake or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an unbonded PC.
Prestress is introduced by using steel material, and precast concrete beams (hereinafter sometimes abbreviated as beams) are converted into precast concrete columns (hereinafter sometimes abbreviated as columns).
It belongs to the technical field of the self-isolation structure method and the self-isolation structure of the RC structure bonded by pressure bonding, and more specifically, the natural period of the RC structure can be increased by allowing the rising of the beam-column joint interface. Self-isolation structure and self-isolation structure.

[0002]

2. Description of the Related Art RC-based structures are relatively inexpensive, have high rigidity, and are excellent in habitability, and are therefore often used in small and medium-sized office buildings and apartment houses. However, the RC system has a high rigidity and a short natural period due to its high rigidity, and a large response occurs to the building due to a disturbance such as an earthquake. Therefore, it is necessary to introduce some seismic isolation technology.

As a typical seismic isolation technology, there is a technology for installing a seismic isolation rubber in which steel plates and rubber are alternately laminated and integrated to achieve seismic isolation. This seismic isolation technology using seismic isolation rubber is effective because the natural period of the RC structure is lengthened to avoid resonance with seismic waves and reduce the input energy to the RC structure.

[0004]

However, the seismic isolation technology using the seismic isolation rubber has the following problems. 1) Although seismic isolation rubber is recognized for its performance, it is very expensive and is easily shunned, and has not yet been widely used. 2) Since seismic isolation rubber is made of organic materials, it requires periodic inspection and maintenance in a relatively short cycle, which increases costs. 3) Most horizontal deformations that occur in buildings occur in the seismic isolation layer where the seismic isolation rubber is installed, so the amount of deformation concentrates on the seismic isolation layer. Therefore, the facility piping / wiring or the secondary member in the seismic isolation layer is required to have a high deformation follow-up performance, and it is difficult and troublesome in design and construction, and the cost increases. 4) Seismic isolation rubber is strong against compressive and shear forces but weak against tensile forces. Therefore, a building having a large aspect ratio such as a high-rise building in which rocking vibration is dominant is easily damaged and cannot be adapted.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a self-isolation structure and a self-isolation structure capable of extending the natural period of an RC structure without using a seismic isolation device or a vibration control device. That is.

A second object of the present invention is to provide a seismic isolation device, a vibration control device, and an RC which is excellent in livability and which greatly contributes to cost reduction while eliminating the need for maintenance associated therewith.
An object of the present invention is to provide a self-isolation structure and a self-isolation structure of a system structure.

[0007] A second object of the present invention is to disperse horizontal deformation such as an earthquake throughout the building, thereby eliminating the need for studying the deformation follow-up performance of equipment piping and secondary members. It is to provide seismic construction method and self-isolation structure. A second object of the present invention is to provide a self-seismic construction method and a self-isolation structure of an RC structure which can be suitably applied to a building having a large aspect ratio such as a high-rise building.

[0008]

As means for solving the above-mentioned problems, an RC according to the first aspect of the present invention is provided.
The self-isolation method for prefabricated structures is based on the pre-stressing of precast concrete beams using unbonded PC steel, and RC joints to precast concrete columns
A self-isolation structure method for a system-based structure, in which the unbonded PC steel material is penetrated in the longitudinal direction of the precast concrete beam, and both ends of the unbonded PC steel are fixed to the precast concrete column, and horizontal force such as an earthquake is applied. According to the present invention, it is characterized in that the unbonded PC steel is allowed to lift up at the beam-column joint interface due to elastic elongation deformation.

[0009] The self-isolating structure of the RC structure according to the second aspect of the present invention includes a precast concrete beam,
Introducing prestress using unbonded PC steel,
A self-isolating structure of an RC-based structure crimp-bonded to a precast concrete column, wherein the unbonded PC steel material penetrates in the longitudinal direction of the precast concrete beam, and both ends of the unbonded PC steel are fixed to the precast concrete column. In addition, according to a horizontal force such as an earthquake, the unbonded PC steel is allowed to lift up at a beam-column joint interface due to elastic elongation deformation.

According to a third aspect of the present invention, in the self-isolation structure of the RC structure according to the second aspect, the precast concrete column is provided with a measure for preventing the end of the precast concrete beam from crushing. Features.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a self-isolation structure and a self-isolation structure of an RC system structure according to the first and second aspects of the present invention. The self-isolation method for RC structures is based on precast concrete beams 2
Is pre-stressed using unbonded PC steel material 3 and pressure bonded to precast concrete column 1.

That is, the precast concrete beam 2
The longitudinal direction of the unbonded PC steel material 3 is penetrated, and both ends 3a, 3a of the unbonded PC steel material 3 are fixed to the precast concrete columns 1, 1 according to a horizontal force such as an earthquake, as shown in FIG. As described above, the unbond P
The present invention is characterized in that it is configured to allow lifting of the beam-column joint interface due to elastic elongation deformation of the C steel material 3 (the invention according to claim 1).

The self-isolation structure of the RC structure constructed by the above-mentioned self-isolation structure method is to pre-stress a precast concrete beam 2 by introducing unstressed PC steel 3 to a precast concrete column 1. It is the structure which did.

That is, the precast concrete beam 2
The unbonded PC steel material 3 is penetrated in the longitudinal direction, and both ends 3a, 3a of the unbonded PC steel material 3 are fixed to the precast concrete columns 1, 1 according to a horizontal force such as an earthquake, as shown in FIG. In addition, the unbond P
The present invention is characterized in that it is configured to allow lifting of the beam-column joint interface due to elastic elongation deformation of the C steel material 3 (the invention according to claim 2).

In this embodiment, one PC steel material 3 is used for one span, but one PC steel is used for many spans.
It can also be implemented using steel material 3. In the present embodiment, a PC steel rod 3 is used as the unbonded PC steel material 3, but the present invention is not limited to this. Substantially the same can be achieved by using a PC steel wire, a PC steel stranded wire, or a multilayer PC steel stranded wire instead of the PC steel rod 3.

The unbonded PC steel material (PC steel rod) 3
As shown in FIGS. 1 and 2, one is provided at substantially the center of the precast concrete beam 2, but the arrangement and the number are not limited thereto. A plurality of PC steel materials (PC steel bars) 3 may be arranged on the beam 2 in a well-balanced and multi-stage manner. For example, the PC steel material 3 is replaced by a PC steel wire, PC
In the case of using a steel stranded wire, the beam may be concentrated at substantially the center of the beam 2 or may be dispersed in a well-balanced manner. Moreover, when implementing with a PC steel wire, a PC steel strand, etc., as shown in FIG. 1, it is not necessary to implement | achieve a PC steel material 3 in a linear shape, and it can also be implemented by bending in an arch shape. . In short, the unbonded PC steel 3
Any shape may be used as long as both ends 3a, 3a protrude from both end surfaces of the precast concrete beam 2, and the shape of the portion built into the beam 2 can be implemented in a flexible form.

The method of fixing the end 3a of the unbonded PC steel material 3 to the precast concrete column 1 is not particularly novel, and is carried out by a method specified in the PC standard of the Architectural Institute of Japan. In the present embodiment, since the PC steel rod 3 is used as the unbonded PC steel material 3, a fixing method using a nut 5 and a supporting plate 6 is generally used as shown in FIG. Although not shown, the column 1
Can be formed by fixing the PC steel bar 3 with the nut 5 and the supporting plate 6 and then filling it with mortar or the like so as to be flush with the side surface of the column 1. Further, since the PC steel material 3 is pretensioned by being tensioned by a hydraulic jack before fixing, the function can be sufficiently exhibited even if the PC steel material 3 is fixed by a button head or a wedge. Incidentally, reference numeral 4 in the figure
Indicates a sheath.

As shown in FIG. 1, both end portions 3a and 3a of the unbonded PC steel material 3 penetrate the opposite side of the precast concrete column 1 and are fixed on the back side thereof. Not done. It is also possible to provide a non-through hole in the column 1 and fix the column 1 at an intermediate position.

As described above, the unbonded PC steel material 3 is not integrated with the pillars 1 and 2 over its entire length, but is tied to the pillars 1 and 1 only at both ends 3a and 3a. I have. Therefore, the unbonded PC steel material 3 is
Is allowed to freely expand and deform at any position, and the design to prevent yielding becomes easy. Therefore, the self-isolating structure of the RC-based structure according to the present invention can provide a precast concrete frame structure which is very safe and has excellent earthquake resistance.

According to the self-isolating structure of the RC structure, the beam 2 rises at the column-beam joint interface (FIG. 4).
As a result, the apparent bending stiffness of the beam 2 becomes smaller as compared with the case where it does not rise, and as a result, the natural period of the RC system structure becomes longer, and the input of the horizontal force at the time of the earthquake becomes smaller. Becomes This mechanism will be described below.

The primary natural period T of the one-span portal ramen shown in FIG. 5 is expressed by [Equation 1]. Incidentally, the symbol B in the figure
Indicates a connection spring.

(Equation 1) For the [number 1], m: mass k: spring constant E _c: Young's modulus of concrete I _c: moment of inertia of the pillar I _b: Beams second moment h: Frame Height l: span length

Next, referring to FIG. 6, regarding the natural period of the gate-shaped ramen when the beam 2 rises at the joint interface, _{Ib in} [Equation 1] is replaced by _Ieff in [ _Equation 2]. It will be.

(Equation 2) For the [Number 2], _{I eff:} Equivalent second moment Mθ when the joint interface is lifted: moment when the rotation angle of the joint interface theta (see FIG. 6) D: Sei Ryo A _p: PC sectional area of the steel E _p: Young's modulus of the PC steel L _p: unbonded length per joint interface one place of PC steel P _o: initial tension of PC steel

The above [Equation 1] and [Equation 2] are represented by specific numerical values as follows. <Examination model> (unit: cm, ton) Pillar: 50 × 50, beam: 80 × 40, l = 700, m = 2
_{0, E c = 350, E} p = 2000, A p = 3.71
6, L _p = 350, P _o = 24.15, θ = 0.02

The specific numerical values of the above study model are expressed by [Equation 1].
Substituting, the natural period of the gate-shaped ramen without lifting
Is required. As a result, T = 0.081 (se
c), I _b= 1.7 × 10⁶Becomes

On the other hand, by substituting the specific numerical values of the above-described study model into [Equation 2], the natural period of the portal-type ramen in the case where the floating occurs is obtained. The result is T = 0.
137 (sec), and I _eff = 1.8 × 10 ⁴ .

Therefore, by the lifting effect of the beam 2,
It can be seen that the natural period of the gate-type ramen is about 1.7 times longer. In a multilayer structure, this effect is even more remarkable, so that the natural period of the RC structure can be made longer. The present invention uses this mechanism as a backbone.

Therefore, according to the self-isolation structure method and the self-isolation structure of the RC structure according to the present invention, the natural period of the RC structure is increased without using the seismic isolation device and the vibration control device. can do. Further, since the seismic isolation device, the vibration control device, and the maintenance associated therewith are not required, it greatly contributes to cost reduction and is extremely excellent in livability.

Furthermore, compared with the case where seismic isolation rubber is used,
Horizontal deformation such as earthquakes can be dispersed throughout the building,
Therefore, it is not necessary to examine the deformation follow-up performance of the equipment piping and the secondary member. The present invention can be suitably applied to a building having a large aspect ratio, such as a high-rise building, which cannot be applied with seismic isolation rubber.
Of course, it can also be implemented in combination with a seismic isolation device or a vibration control device.

The self-isolation structure of the RC structure may be further implemented by taking measures to prevent the end of the precast concrete beam 2 from crushing the precast concrete column 1 as shown in FIG. Claim 3). This crush prevention measure is to absorb the compressive deformation and to crush the end of the precast concrete beam 2 on the side surface 1a of the precast concrete column 1 which is compressed by the rotational deformation caused by the rising of the precast concrete beam 2. This is implemented by providing a member (not shown) such as an elastic body, a cushioning material, or the like, for preventing the occurrence of the vibration. By the action of the member such as the elastic body,
It is possible to provide a self-isolating structure of an RC-based structure capable of preventing the precast concrete beam from being damaged as much as possible and maintaining the self-isolating function permanently.

[0030]

According to the self-isolation structure method and the self-isolation structure of the RC structure described in claims 1 and 2,
The natural period of the system structure can be extended without using the seismic isolation device and the vibration control device. Further, since the seismic isolation device, the vibration control device, and the maintenance associated therewith are not required, it greatly contributes to cost reduction and is extremely excellent in livability.

Further, horizontal deformation such as an earthquake can be dispersed throughout the building as compared with the case where seismic isolation rubber is used, and therefore, examination of the deformation follow-up performance of equipment piping and secondary members becomes unnecessary. The present invention can be suitably applied to a building having a large aspect ratio, such as a high-rise building, which cannot be applied with seismic isolation rubber.
According to the self-isolating structure of the RC structure described in claim 3, the self-isolating function can be maintained permanently.

[Brief description of the drawings]

FIG. 1 is an elevation view showing a self-isolating structure of an RC-based structure according to the present invention.

FIG. 2 is a cross-sectional view of a precast concrete beam.

FIG. 3 is a sectional view showing a fixing portion between an end portion of an unbonded PC steel material and a pillar.

FIG. 4 is an elevational view showing a rising state of the self-isolation structure of the RC structure according to the present invention.

FIG. 5 is a model diagram of a portal-type ramen shown to explain the mechanism of the self-isolation function of the RC structure according to the present invention.

6 is a model diagram showing a beam-column joint when a horizontal force such as an earthquake occurs in the portal-type ramen of FIG. 5;

[Explanation of symbols]

 1 Precast concrete column 2 Precast concrete beam 3 Unbonded PC steel 4 Sheath

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yoshihiro Ota 1-5-1, Otsuka, Inzai City, Chiba Prefecture F-term in Takenaka Corporation Technical Research Institute F-term (reference) 2E125 AA04 AA14 AB12 AC02 AG02 AG04 AG12 AG41 BB01 BB08 BB22 BB30 BC09 BD01 BE07 BE08 BF06 CA05 CA13 CA14 EA00 EB00

Claims (3)

[Claims] 1. A self-isolation method for an RC structure in which a prestressed precast concrete beam is joined to a precast concrete column by introducing a prestress using an unbonded PC steel material, wherein a longitudinal direction of the precast concrete beam is used. The unbonded PC steel material is penetrated through, and both ends of the unbonded PC steel material are fixed to the precast concrete columns, and according to a horizontal force such as an earthquake, the rising of the beam-column joint interface caused by the elastic extension deformation of the unbonded PC steel material is reduced. A self-seismic construction method for RC-based structures, characterized in that it has an allowable configuration. 2. A self-isolation structure of an RC-based structure in which a precast concrete beam is prestressed by using an unbonded PC steel material and pressure-bonded to a precast concrete column, wherein a longitudinal direction of the precast concrete beam is used. The unbonded PC steel material penetrates through, and both ends of the unbonded PC steel material are fixed to the precast concrete columns, and according to a horizontal force such as an earthquake, the lifting of the beam-column joint interface due to the elastic extension deformation of the unbonded PC steel material is allowed. A self-isolating structure of an RC structure, characterized in that it is configured to perform the following. 3. The self-isolating structure for RC-based structures according to claim 2, wherein the precast concrete columns are provided with measures to prevent crushing of the ends of the precast concrete beams.